Inward flow turbine



March 16, 1965 P. J. J. DU PREEZ 3,173,656

INWARD FLOW TURBINE Filed Dec. 9, 1963 2 Sheets-Sheet 2 INVENTOR.

United States Patent 3,173,656 INWARD FLOW TURBINE Pieter Johannes Jacobus du Preez, 32 Crummoclr Ave, Northrand, Transvaal, Republic of South Africa Filed Dec. 9, 1963, Ser. No. 329,058 Claims priority, application Republic of South Africa, Dec. 13, 1962, 5,258; May 11, 1963, 2,049 11 Claims. (Cl. 253-52) The present invention relates to inward flow turbines.

An inward flow turbine, in accordance with the invention, includes walls defining an impeller chamber; an impeller mounted to rotate within the impeller chamber; and an accelerating system having a flow inlet, for convcrting pressure energy in a working fluid into kinetic energy and for directing fluid flow onto the impeller through a zone between the system and the impeller; and includes flow bleed-off means for bleeding 01f working fluid from the zone at varying rates of flow, the bleed-off means being adapted tomaintain sensibly constant the rate of flow through the accelerating system, thereby maintaining sensibly constant the pressure in the zone under varying load demands on the turbine and thereby regulating the speed of the impeller.

The bleed-off means for a liquid may include a stand pipe connected to the zone, the stand pipe having a flow outlet opening at a predetermined height above the level of the flow inlet. It may also include a pressure control or relief valve connected to the zone and set at a predetermined pressure to relieve excess pressure in the zone.

A control valve may be provided in series with flow .from the zone, to control the flow characteristic.

Alternatively, the bleed-off means may include walls defining a recirculating impeller chamber connected to the zone, a recirculating impeller within this chamber and of larger diameter than the impeller and co-axially con nected to it, and a flow conduit connecting this chamber to the flow inlet.

The flow conduit may diverge from the recirculating impeller chamber to the flow inlet to convert velocity head into pressure head. The bleed-off means may include further, a control valve in the flow conduit, to control the flow characteristic between the recirculating impeller chamber and the accelerating system.

In yet another embodiment, the bleed-off means may include walls defining an auxiliary impeller chamber connected to the zone, an auxiliary impeller within this chamber and co-axially connected to the impeller, and a flow conduit connected to this chamber and having a flow outlet opening, the auxiliary impeller being adapted to act as a pump impeller, and to generate a pressure in the working fluid in the auxiliary impeller chamber. If it is desired to pump toa pressure exceeding that at inlet, then the auxiliary impeller is made larger in diameter than the impeller.

The accelerating system may include a volute casing or guide vanes spaced peripherally around the impeller, or both a volute casing and guide vanes the zone being disposed between the guide vanes and the impeller periphery, or between the volute casing and the impeller Periphery.

The invention will now be described by way of example, with reference to the accompanying drawings in which several specific embodiments are shown.

In the drawings:

FIGURE 1 shows a diagrammatic axial section of one embodiment of the invention;

FIGURE 2 shows a diagrammatic axial section of another embodiment of the invention;

FIGURE 3 shows schematically a side elevation of an installation embodying the turbine of FIGURE 1 or FIG- URE 2;

3,l73,656 Patented Mar. 16, 1965 FIGURE 4 shows schematically a side elevation of an installation embodying the turbine of FIGURE 2;

FIGURE 5 shows an axial section of a composite impeller comprising a main impeller and a recirculating or auxiliary impeller; and

FIGURE 6 shows a front .elevation of a main impeller, the auxiliary or recirculating impeller having been removed.

Referring to FIGURE 1 of the drawings, reference numeral 10 refers generally to an inward flow turbine, comprising walls 12 defining an impeller chamber 14 within which is rotatably mounted an inward flow impeller 16, having fast with it an output shaft 18, rotatably through gland 20 in the walls 12 of the impeller chamber.

The turbine includes also casing 22 defining a volute chamber 24 leading into guide vanes 26 spaced peripherally around the impeller chamber 14. A zone 28 occurs between the guide vanes 26 and the outer periphery of the impeller 16 having vanes 30 and an axial outlet opening 32 defined by neck flange 34 passing rotatably through a gland 36. The volute chamber 24 together with the guide vanes 26 constitute the accelerating system of the turbine.

Bleed-off means in the form of a volute casing 38 is in communication with the zone 28. The bleed-off means includes further a stand pipe 40 (see FIGURE 3) having a flow outlet opening 42 at a predetermined height above the flow inlet 44. Instead of the stand pipe 40 having a flow outlet opening 42, at a predetermined height, there may be provided a pressure control or relief valve 46, set to open under a predetermined pressure. Control valve 45 is provided to control the flow characteristic from the zone 28.

' In operation, the flow inlet 44 will be connected to a supply of working fluid under pressure. It will be noted that the flow inlet 44, converges at 48, where it joins the casing 22, and this convergence at 48, also forms part of the accelerating system. The pressure head of the Working fluid is converted into velocity head in the accelerating system, and the working fluid is passed from the volute 24 through the guide vanes 26 in the direction of arrow 50 passing through the zone 28. Thence it passes into the impeller 16 and through it, thereby driving the impeller. The working fluid passes axially out of the impeller in the direction of arrow 52, through the impeller outlet opening 32, and thence out of the outlet pipe 33 (see FIGURES 3 and 4).

The bleed-off volute 39, defined by the casing 38 is in communication with the zone 28, and with the stand pipe 40. The pressure in the zone 28, is governed by the height of the outlet opening 42 of the stand pipe 40 for liquids, or by the setting of the pressure relief valve 46. The arrangement is such, that any excess flow of working fluid, will overflow out of flow outlet opening 42 or past the relief valve 46. The overflow pressure through the flow outlet opening 42, or through the pressure relief valve 46, will be substantially constant, and this will also be the pressure in the zone 28. Variation of load demand on the output shaft 18 will cause corresponding variations in the quantity of working fluid overflow, an increase in the load demand on the output shaft, being accompanied by a decrease in the amount of working fluid going out of the flow outlet opening and conversely. The pressure in the zone 28 being the back pressure of the impeller, is therefore maintained sensibly constant, by the pressure head in the stand pipe, or by the pressure of the relief valve, and thereby provides speed regulation of the impeller under varying load conditions.

Referring now to FIGURE 2 of the drawings, the construction of this turbine is substantially the same as that shown in FIGURE 1, except that a composite impeller fiflis provided comprising a main impeller 60a and a recirculating or auxiliary impeller 6%. The mainimpeller 60a is substantiallythe same as impeller 16 previously described, but it has means for attaching to it the recirculating or auxiliaryimpeller 60b having vanes projecting outwardly into the. volute 39. The diameter of therecirculating or auxiliary impeller 60b is determined by the amount of pressure required in the volutej'3 9, and may have a diameter smaller than the main impeller 60a, equal to' it, or greater. This composite, impeller 60' will be described later in greater detail.

For speed regulation, the volute 39 will be connected via a flow conduit 62 "diverging away from 'thevolute 39' and connected to the new inlet conduit 44 (see FIG In operation, the recirculating or auxiliary impeller, 7

60b, will act as a pump, and will draw workingfluid from the zone 28. For a given load on the output shaft.

18 therefore, a certain amount of recirculation of working fluid from the volute 39 into the flow inlet 44 will take place. If the load on the. output shaft decreases, thenthe main impeller 60a will tend to speed up, thereby having a tendency to increase'the pressure in zone 28, and

the auxiliary impeller 60b will tend tospeed up with itand will. tend to draw more Working fluid from. the zone 28 for recirculation, thereby tending to reduce the pres.-

surein zone 28, and thus maintaining constant the pressure in the zone 28 and hence the speed of the impeller.

If the load on the output shaft increases, then the amount of working fluid recirculated will be correspondingly less.

In this way the flow through the accelerating system and the pressure of the working fluid in the zone 28 is maintained sensibly constant, and hence the speed of the impeller are maintained sensibly constant.

If.instead of the recirculating fiow'conduit '62 con-' uected to the volute 39, there is provided a delivery pipe such as 40 (see FIGURE 3), then. the recirculating impeller 6% will operate as anauxiliary impellervand the whole installation becomes a turbine. pump. whereby it becomes possible for Working fluid to be pumped to a desired pressure above that at the impeller and to a press sure even greater than'that of the working fluid connected to theflow inlet 44'. Such an installation will.

find practical use, in the pumping of water available. under a low head, to a height greater than the head of the, 1

working fluid available- 'Speed regulation will still be obtained, even'when a turbine pump incorporating the invention is used .to drive a load such as a generator.

FIGURES 5 and 6 show detailsof construction of in the impeller chamber; and an accelerating system having a flow inlet, for converting pressure energy in a working fluid into kinetic energy and for: directing fluid flow ontothe impeller through a zone between the system and the impeller; and which includes flow bleed-oh. means for bleeding 01? working fluid from the zone at varying rates of flow, the bleed-off means being adapted to maintain sensibly constant the rate of flow of working fluid through the accelerating system, thereby maintaining sensibly constant the pressure in; the zone under varying load'demands on the turbine and thereby regulating the speed of the impeller.

2.v A turbine according to claim 1, in which the bleedoff means includes a stand pipe connected to the zone,

the stand pipe having a flow outlet opening at a p'redetermined height above thelevel of theflow inlet.

3. A turbine according to claim 1, in which the bleedoii. means includes a relief valve connected tothe zone and set at a predetermined pressure to'relieveexcess pressure in the zone." V V I g g '4. A turbine according to claim 2,;in which a control valve is provided infseries withflowfrom the zone, to

control the flow characteristic.

,impeller; and which includes flow bleed-oifmeans for bleeding 'oif working fluid fromthe zone at varying rates of, flow, the bleed-oil? means beingadapted to maintain sensibly constant the rate of flow ofworking fluid through the accelerating system, ,therebymaintaining sensibly constant the pressure in thezoneunder varying loaddemands. on the turbine, and thereby regulating the speed of the impeller; and in which the bleed-off means includes walls defininga re-c'irculating impeller" chamber connected to the zone, a re-circulating impeller within this, chamber and of larger diameter" than the impeller and co-axially connected to'it, and a flow'conduit connectlng thisc'hamber to theflow inlet. p 6. A turbinelaccording to claim 5, in which the flow conduit diverges from the re-circulating impeller chamber to the flow inlet; to convert velocity head into pressure head. r

7. A turbine'according to claim '5, in which the bleedoit means includes further a control valve in the flow conduit, to control theflow between the re-circulating irnpeller chamber and the flow inlet.

I 8. Anzinward flow; turbine including walls defining an impeller chamber; an impeller mounted to rotate within the impeller chamber; anda n accelerating system having a flow inlet, for convertingfpressure energy in a working the composite'impeller and of the main impeller 60a.

The main impeller 60a, has a flange region 70. connected to the neck flange 34'and projecting outwardly from the axis of the impeller. peller tlb'having vanes 72,-.is1 attached via .the holes 74 to the flange region .70. The main impeller 60a is secured to the outputshaft 18,'by meansof a'n end nut 76, which draws theimpeller 60aagainst a shoulder provided on may be disposed at any desired angle relative to a radius of the impeller, namely, backward, radial, or forward.

By way of explanation, by flow characteristics is The recirculating or auxiliary imw fluid into kinetic energy and for directing fluid flow onto the impeller through a zone'between the system "and the impeller; and :which includes flow bleed-off means for bleeding off workinglfluid from the zone at varying rates 7 stant the pressure in the zone under varying load demands the output shaftv 18. The. recirculating of auxiliary im j meant the degree of conversion of kinetic energy into pressure energy.

I claim: i 1. An inward flow turbine, including walls defining an impeller chamber; an impeller mounted torotate Withinthe auxiliary impeller chamber.

on the turbine and thereby regulating the speed of the impeller; and in which the bleed-off means includes walls defining an auxiliary impeller chamber connected to the zone," an auxiliary impellerwithin' this chamber and coaxially connected to the impell'enand a flow conduit con- 7 'nected to this chamberand havin'ga flow outlet opening, f the auxiliary impeller being adapted to act as a pump impeller, and togenerate a pressure in the working fluid I 9. A turbine according to claim 8 in which the auxiliary impeller has a diameter larger than that of the impeller and is adapted to generate a pressure in the Working fluid inthe auxiliary chamber exceeding the pressure of the fluid at inlet, and in which the fluid conduit has a how outlet opening at a pressure greater than that at inlet.

10. A turbine according to claim 8 in which a control valve is provided in the flow conduit, to control the how between the auxiliary impeller chamber and the flow outlet opening.

11. An inward flow turbine, including Walls defining an impeller chamber; an impeller mounted to rotate within the impeller chamber; and an accelerating system having a flow inlet, for converting pressure energy in a Working fluid into kinetic energy and for directing fluid flow onto the impeller through a Zone between the system and the impeller and which includes flow bleed-oil means for bleeding off working fluid from the zone at varying rates of flow, the bleed-off means being adapted to maintain sensibly constant the rate of flow of working fluid through 6 the accelerating system, thereby maintaining sensibly constant the pressure in the zone under varying load demands on the turbine and thereby regulating the speed of the impeller; and in which the accelerating system includes guide vanes spaced peripherally around the impeller, the zone being disposed between the guide vanes and the impeller periphery.

References tilted by the Examiner UNITED STATES PATENTS 810,955 1/06 Lund 253-59 LAURENCE V. EFNER, Primary Examiner.

ROBERT M. WALKER, Examiner. 

1. AN INWARD FLOW TURBINE, INCLUDING WALLS DEFINING AN IMPELLER CHAMBER; AN IMPELLER MOUNTED TO ROTATE WITHIN THE IMPELLER CHAMBER; AND AN ACCELERATING SYSTEM HAVING A FLOW INLET, FOR CONVERTING PRESSURE ENERGY IN A WORKING FLUID INTO KINETIC ENERGY AND FOR DIRECTING FLUID FLOW ONTO THE IMPELLER THROUGH A ZONE BETWEEN THE SYSTEM AND THE IMPELLER; AND WHICH INCLUDES FLOW BLEED-OFF MEANS FOR BLEEDING OFF WORKING FLUID FROM THE ZONE AT VARYING RATES OF FLOW, THE BLEED-OFF MEANS BEING ADAPTED TO MAINTAIN SENSIBLY CONSTANT THE RATE OF FLOW OF WORKING FLUID THROUGH THE ACCELERATING SYSTEM, THEREBY MAINTAINING 